June 1, 2011

Effect seen no matter how many drugs are given, analysis of 1975-2010 trial data shows

Asian non-small cell lung cancer (NSCLC) patients survive longer than Caucasians no matter how many drugs are given in a first-line setting, and the effect was apparent both before and after the introduction of targeted therapies in the early 2000s, according to research published in the June issue of the Journal of Thoracic Oncology.

"It is recognized Asian patients with a common type of lung cancer, the non-small cell type, have a better survival than Caucasian patients when treated with chemotherapy," said Dr. Ross Soo, senior consultant in the Department of Haematology-Oncology at the National University Hospital in Singapore. "What wasn't known previously was whether this effect was seen in patients given just one or a combination of drugs. Furthermore, the improved survival could have been due to the better chance of targeted therapy working in Asians.

"We analyzed studies published in the past 35 years in which chemotherapy was given to patients in the advanced stage," Dr. Soo said. "We found Asian patients indeed had a longer survival and also a higher chance of tumor shrinkage regardless of the number of chemotherapy drugs given in the first-line setting. We also found Asian patients lived longer than Caucasian patients in the era both before and after the use of targeted therapy such as gefitinib and erlotinib. These findings may impact on the design and conduct of international lung cancer trials as more Asian countries are now participating in such studies."

For all drug regimens across those 35 years, Asian patients experienced median overall survival (OS) of 10.1 months while white patients' overall survival was 8.0 months. For monotherapy, the median OS was 9.9 months for Asians and 6.8 months for whites. For platinum-based doublets, median OS was 10.4 months for Asians and 8.6 months for whites. For combinations of three or more drugs, median OS was 9.4 months for Asians and 8.0 months for whites.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib were introduced in many Asian countries in 2002, and their use was associated with an improvement in OS of Asian patients. In the pre-EGFR TKI years (up to and including 2001), median OS was 9.1 months for Asians and 7.3 months for whites; from 2002 onward that gap widened to 11.0 months for Asians and 8.9 months for whites.

In single-agent studies done since 2002, the median OS was significantly higher in Asian than in white studies: 11.8 vs. 7.1 months. It also was notably higher than the years prior to 2002, when OS was 8.9 months for Asian and 6.5 months for white patients.

In platinum doublets the median OS was 11.0 months for Asians and 9.5 months for whites; that compared with pre-2002 OS rates of 9.1 months for Asian and 7.6 months for white patients. For regimens of three drugs or more, post EGFR TKI-approval median OS was 9.5 months for Asians and 8.2 months for whites, compared with 9.3 and 7.6 months, respectively, before 2002.

"Ethnic differences in survival and response rate to chemotherapy exist and should be considered in clinical trial designs especially in the global context," researchers wrote.